Aircraft radiator



- Au 4 1 42. J.M.GW1--,J R 2,291 622 AIRCRAFT RADIATOR Filed July 20, 1940 3 Sheets-Sheet 2- Fig.2.

lQ- losegh ATTORNEYS g- 4, 1942 J. M. GWINN, JR I 2,291,622

AIRCRAFT RADIATOR FiledJuly 20, 1940 3 Sheets-Sheet 3 INVENTOR JosephMfiWinnJn BY z ATTORN EYS Patented Aug. 4, 1942 'UNITED STATES PATENT OFFICE I 2,291,622 AIRCRAFT RADIATOR Joseph M. Gwlnn, In, Buffalo, N. Y., assignor to Bell Aircraft Corporation, Buffalo, N. Y., a corporation of New York Application July 20, 1940, Serial No. 346,587

6 Claims.

This invention relates to heat exchange devices and more particularly to radiators of the type wherein heat transfer action is provided between a liquid and a gas. For example, in the case of an airplane employing a chemical liquid as the engine cooling medium an airstream is directed through the radiator for cooling the liquid; and the present invention has for one of its objects the provision of an improved form of radiator of this type which is of improved efficiency. Another object of the invention is to provide a radiator core which is characterized by maximum heat transfer surface area in a given volume of core. Another object of the invention is to provide, in a radiator of a given frontal area, an increased proportion of free air area. Another object of the invention is to provide a given heat transfer action through use of a reduced amount of heat transfer liquid. Another object of the invention is to provide a radiator in which a given heat transfer action is obtained'in return for a reduced air pressure drop through the radiator. Another object of the invention is to provide a radiator of the character described wherein a given heat transfer action is obtainable in return for a reduced quantity of air flow therethrough. Other objects and advantages of the invention will appear in the specification.

In the drawings:

Fig. 1 is a fragmentary front elevation of a radiator of the invention at one side of a longitudinal plane of symmetry thereof;

Fig. 2 is a side elevation of the radiator of Fig. 1;

Fig. 3 is a fragmentary plan view of the map ator; I

Fig. 4 is a fragmentary section on an enlarged scale through 'a typical portion of the radiator core, taken transversely of the direction of air flow therethrough;

Fig. 5 is a perspective, on an enlarged scale, of

bers are arranged to have their end portions connected together in fluid tight relation, and the portions of the tubes intermediate of their ends are so formed as to provide novel liquid carrying passages therebetween and novel air conducting channels therewithin.

In Figs. 1 to 6 the tubular members'so employed are illustrated as being of two different forms; and the major portion of the radiator core is fabricated by assembly of alternate rows of tubes H! of the type illustrated in Fig. 5 and tube units 20 which are provided by disposing two tube members 22 of the form illustrated in Fig. 6 in back-to-back relation. The individual tube members are of seamless metal form such as may be economically manufactured by means of impact extrusion processes, or the like. Tubes l0 and units 20 are of hexagonal sectional form at their ends and are soldered or otherwise fastened together at their end sections so as to provide fluid tight connections therebetween. The tube members 22 and the tube units 20 are of uniform sectional form and dimensions throughout their lengths, but the tube members ID are reduced in sectional dimensions intermediately of their ends as indicated at H (Fig. 5). Consequently, liquid carrying spaces are provided between the reduced tube portions ll and adjacent tube units 20 for free circulation of liquid therethrough in generally vertically directed paths, as viewed in the drawings. The interiors of the tubular members l0 and 22 provide the air carrying spaces of the radiator.

As illustrated in Fig. 6, the tubular members 22 are semi-hexagonal in sectional form and comprise side walls 24, 25, 26 and 21. When assembled into paired tube units '20 the wall portions 24 of the paired members provide, in effect, air cooled fins disposed longitudinally through the interiors of the tube units 20. Hence, the heat transfer action of the air moving through the tubes operates directlythrough the walls of the tubes l0 upon the liquid surrounding them and directly through the wall portions 25, 26, and 21 of the tube units 20 upon the liquid in contact therewith, and indirectly upon the liquid in contact with the walls 25, 26 and 21 or wall portions 24. It will be understood that the fin wall portions 24 are integral with the wall portions 25 and 21' of the respective tube members 22, and are therefore thermally bonded thereto in ideal manner from the standpoint of heat transfer efficiency. Hence, a novel and improved form of tube unit is provided which by use of only easily and economically manufactured parts procures additional indirect heat transfer effects through means of fins locatedinteriorly of the air passages thereof. I am aware that radiators have previously been devised which embody internal fin elements for indirect cooling purposes, but such prior forms of radiators have been defective from the standpoint of the quality of the thermal bonds between the parts thereof and/or the difficulties and expenses attending their manufacture. In the case of the present invention utmost simplicity and ruggedness of construction is obtained as well as optimum heat transfer action throughout-the radiator parts without manufacturing difliculties and at minimum cost.

By reason of the organization of the tube units as illustrated and described, the volume of the cooling liquid in any unit section of the core of the radiator is approximately one-half that of the cooling liquid in a radiator. core section of similar dimensions which is composed solely of tubular members of the type of the tubes l0. Also, the composite surface area of the air contacting metal portions of the radiator is substantially increased as compared to the conventional type of radiator core hereinabove referred to. The authorities agree that heat transfer action takes place more readily through a liquid-wetted metallic surface than through the corrugations of plate 32.

an air contacting metallic surface, and conseinvention.

I am aware that various forms of combination direct and indirect heat transfer units have been previously devised, and that it is not new, per se, to employ fluid conveying members of geometric sectional forms in connection with the fabrication of radiator cores. For example,

' be desirable.

in the case of the French Patent 723,740 to M.

As will be observed by an examination'of Fig. I

l, the tube units 20 are preferably so arranged throughout the core body so that the wall members 24 thereof are disposed in intersecting planes, and thust continuity of soldered joints throughout the structure is avoided and the completed core assembly is thereby free of natural cleavage planes such as would otherwise reduce the struc tural strength of the unit.

The radiator core is enclosed at its top and bottom and sides by means of sheet metal casing elements so as to complete enclosure of the liquid to be cooled thereby. As illustrated in Figs. 1-3, the top and bottom portions of the core are enclosed by means of plates 30 and gitudinally of the core unit as at 42.

the sides are enclosed by means of plates 32; the plates 30 and 32 being preferably of corrugated sectional form as illustrated herein for stiffening purposes and so that they may successfully withstand pressure of the cooling liq- "id. The plates 30 and 32 are connected in fluid tight relation at their marginal edge portions to provide a fluid tight enclosure for the cooling liquid in conjunction with the soldered air inlet and outlet end sections of the core. Corner plates 34 of generally U shaped sectional form and havingtheir edges escalloped'to complement and interfit with adjacentportions of the casing plates and core structure are connected thereto at the corner sections of the radiator so as to close the latter and complete the fluid tight assembly of the radiator casing. As shown in Fig. l, the escalloped edge 36 of one flange of corner plate 34 interfits with casing plate 35, while as shown in Fig. 2, the escalloped edge 31 of the other flange of the corner plate interfits with A binding strip 35 (Fig. 4) shaped complementary to and nested against the outer edge portions of the core unit at the front and rear ends thereof is preferably soldered or otherwise connected to the core unit to assist in binding the tube elements thereof into integral unit form.

A liquid inlet conduit manifold 40 is illustrated in connection with the top plate 30, and it will be understood that there may be furnished as many of such manifolds as may be deemed to As illustrated in Fig. 1, the upper section of the radiator core, above line 38, is preferably formed solely by tube elements It) so as to provide liquid circulating spaces throughout every portion of the upper core section with a view to augmenting dispersion of inflowing liquid horizontally throughout the entire core unit.

The lowermost core section, below line 39 in Fig. l, is similarly formed solely of tube elements l0 so that -an increased proportion of liquid carrying space is provided'in this section of the core adjacent the outlet conduits of the radiator. As illustrated in Fig. 1, an outlet manifold is formed interiorly of the lowermost core section by complete omission of tube elements at a portion thereof so as to provide an opening lon- At one end of the core the opening 42 is in communication with an outlet conduit 44, and it will be understood that as many such manifold openings and 'outlet conduits may be provided as may be declosure plug 46 therein in fluid tight relation. A

wash out port is conveniently arranged in the bottom casing plate 30 and it is normally closed 0 by means of a cover 50.

It will be observed that the rows of the tube units 20 are interrupted at intervals by inclusion of tube members It] therein so as to provide for liquid flow through the core transversely of the direction of the general movement of liquid between the inlet and the outlet manifolds. For example in Fig. 1 all of the tubes in the horizontal rows indicated between the pairs of parallel lines 41 may consist of tube members I0. Thus, in the event that stoppages occur in portions of the liquid carrying space of the radiator, the flow of liquid will not be interrupted throughout the entire vertical section of the core which includes the stoppage because transverse flow will by-pass the stoppage and the radiator will thereby continue to function with only slightly reduced efficiency.

Fig. 7 illustrates another form of core construction for the major portion of the core unit, and in this case the core Section is fabricated by assembly of a plurality of tube units 60 disposed in rows arranged alternately with rows of tube units 20 as hereinabove described. The tube units 60 each comprise a pair of tube elements 62 which are semi-hexagonal in sectional form at their opposite ends, and in this respect the tube elements are similar to the tube elements 22 hereinabove described. However, the tube elements 62 are of semi-circular and reduced dimensional form intermediately of their ends, and in this respect differ from the form of the tube elements 22. The tube elements 62 are so formed that the adjacent wall portions thereof which are disposed in abutting relation when assembled in pairs are of flat outer surface form throughout their lengths, and consequently when the tube elements 62 are arranged in pairs no liquid spaces are provided therebetween and the paired unit provides the interior fin effect hereinabove described with respect to tube units 20 whereby the manufacturing economies and indirect heat transfer action of the invention is obtain. There is thus provided a core section construction wherein each of the tube units thereof is internally finned for air contacting purposes, and liquid carrying spaces are provided adjacent the outer surfaces of the tube units 60 by reason of the reduced sectional dimensions thereof intermediately of their ends;

Another form of core section construction is tube elements 12 thereof are semi-hexagonal in sectional form instead of semi-circular as in the case of Fig. '7. It will be understood'that the heat transfer features and economies of manufacture hereinabove described may thus be obtained by various changes in detail without departing from r the spirit of the invention or from the scope of the appended claims.

I claim:

1. A radiator core comprising a plurality of tube units disposed parallel to one another and nested in rows to form a core unit, said tube units being formed with end portions having complementary sectional forms and united thereat in fluid-tight relation, the tube units of alternate rows of said tube units being of reduced sectional dimensions intermediately of their ends thus providing intercommunicating passageways therebetween for the fluid to be cooled, the other alternate rows of said tube units being composed of paired tubular elements having complementary side portions thereof arranged in adjacent abutting relation, the rows of said paired tubular elements being interrupted periodically by inclu-- intermediately of their ends thus providing intercommunicating passageways therebetween for the fluids to be cooled, the other alternate rows of said tube units being composed of paired tubular elements having complementary side portions thereof in adjacent abutting relation, and an end section composed of a plurality of tube units, all of which are of reduced sectional dimensions intermediately of their ends to provide a manifold efiect throughout said end section.

3. A radiator core comprising an end section and a center section, said center section being composed of a plurality of tube units disposed parallel to one another and nested in rows to form a core unit, said tube units being formed with end portions having hexagonal sectional forms and united thereat in fluid-tight relation, the tubeunits of alternate rows of said tube units being of circular sectional form and of reduced sectional dimensions intermediately of their ends thus providing intercommunicating passageways therebetween for the fluid to be cooled, the other alternate rows of said tube units being composed of paired tubular elements of semi-hexagonal form having complementary side portions thereof arranged in adjacent abutting relation, said end section being composed solely of tubular elements of hexagonal sectional end form and of reduced circular sectional form intermediately of their ends.

4. A radiator core comprising a plurality of tube units disposed parallel to one another and nested in rows to form a core unit, said tube units being formed with end portions having complementary sectional forms, the tube units of alternate rows being of reduced sectional dimensions intermediately of their ends, thus providing passageways therebetween for fluid to be cooled, the other alternate rows of said tube units being composed of paired tubular elements having complementary side portions therof arranged in adjacent abutting relation, at least some of the rows of said paired tubular elements being interrupted by inclusion of a tube unit of reduced sectional dimensions so as to provide transverse flow of liquid through said rows of tube units.

5. A radiator core having inlet and outlet connections and comprising a plurality of tube units disposed parallel to one another and nested in rows to form a core unit, said tube units being formed with end portions having complementary sectional forms, the tube units of alternate rows being of reduced sectional dimensions interme-' diately of their ends, thus providing communicating passageways for fluid, the other alternate rows being composed of paired tubular elements having complementary side portions thereof in abutting relation, and the tube units adjacent one of said connections being of reduced sectional dimensions intermediately of their ends to provide a manifold connecting said one of said connections to said intercommunicating passageways.

6. A radiator core comprising a plurality of tube units disposed parallel to one another and nested in rows to form a core unit, said tube units having end portionsof hexagonal sectional form and being united thereat in fluid-tight relation, the tube units being arranged with a long diagonal of each hexagonal form extending substantially parallel to the direction'of major extent of said rows and each having one face of the hexagonal form thereof in registry with a like.

face of an adjacent tube of the same row whereby each row is substantially zig-zag in form, the

tube units of alternate rows being of reduced sectional dimensions intermediately of their ends thus providing intercommunicating passageways for liquid through the core, and the tube units of the other alternate rows being of hexagonal form of constant sectional dimensions from end to end thereof whereby the portions thereof in contiguous relation to adjacent tube units of the same row provide walls devoid of liquid passages therethrough, and each of the latter tube units comprising a pair of separately formed semi-hexagonal tubular elementsarranged in abutting relation from end to end thereof providing other walls devoid of liquid passages therethrough, said other walls being substantially parallel to walls of the hexagonal form. 1

JOSEPH M. GWINN, JR. 

